I can't seem to get Concurrency limits to actually...
# ask-communitye
Eric Albanese
03/14/2025, 4:46 PMI can't seem to get Concurrency limits to actually work. Self hosted Prefect 2.20.16. I have one (EC2/Docker) work pool with one work queue named default. Everything runs OK normally. I've tried setting Concurrency limits under
ConcurrencyWork Pool > Flow Run ConcurrencyWork Pool > Work Queue > Flow Run Concurrencyb
Bianca Hoch
03/14/2025, 6:21 PMHi Eric! I'd recommend checking for older flow runs that are stuck in a
RunningPendinge
Eric Albanese
03/14/2025, 6:35 PMAh no luck with that, nothing backlogged
Eric Albanese
03/14/2025, 6:37 PMOh hmm. I've been trying using 3 as a limit with no luck. Upped that to 100 and then jobs started. So I think you may be on to something w/ other jobs backlogging, but I can't seem to find what/how
Eric Albanese
03/14/2025, 6:38 PMScreenshot 2025-03-14 at 11.38.05 AM.png
Eric Albanese
03/14/2025, 6:46 PMok so Flows won't run anything up to 19. I change it to 20 and then jobs finally run 🤔. So there does seem to be 19 jobs that are considered running for concurrency purposes but not seeing anything in an active state. Deleted all previous
Cancelledb
Bianca Hoch
03/14/2025, 8:02 PMhmmm.. 19 is such an odd number (literally). You're only setting the concurrency limit at the work queue level, correct? No concurrency limits have been applied to a worker, work pool, or even at the deployment level?
e
Eric Albanese
03/14/2025, 10:37 PMYes very odd (lol). Only at the queue level. Tried setting limits at the other places but the same behavior
b
Bianca Hoch
03/17/2025, 2:43 PMTo keep the troubleshooting train rolling, here's a script that may help rule out the possibility of hidden flow runs that are occupying those concurrency slots. At a high level, the script look for flow runs stuck in
BAD_STATESBianca Hoch
03/17/2025, 2:45 PMMy thinking is you can add a few more states to the
BAD_STATESPendinglist_flow_runs_with_state7 Views